Proteins

Question 1

What are proteins made up of?

Answer 1

Amino acids

Question 2

What are amino acids made up of?

Answer 2

• Central carbon bonded to hydrogen
• Amino group (NH2)
• Carboxylic group (COOH)
• R group (side chain)

Question 3

R group

Answer 3

Determines the physical and chemical structure of a protein

Question 4

How are amino acids joined to form proteins?

Answer 4

Through a peptide bond which requires energy and removes a molecule of water

Question 5

How many amino acids are there?

Answer 5

140

Question 6

How many amino acids make up a protein?

Answer 6

20

Question 7

Side chains

Answer 7

• Large or small
• Charged or neutral
• Form hydrogen or disulfied bonds with other amino acids
• Hydrophobic or hydrophilic

Question 8

Primary protein structure

Answer 8

• Amino acid sequence
• R groups located on opposite sides of chains
• No interactions

Question 9

Secondary protein structure

Answer 9

• Determined by number and sequence of amino acids
• Formed by chemical reactions in the primary structure
• Space between amino acids

Question 10

Tertiary protein structure

Answer 10

• 3D structure
• Formed by interactions of amino acids or side chains
• Globular-like structure
• Fibrous structure

Question 11

Quaternary protein structure

Answer 11

• Space between sub-units
• Formed by 2 or more polypeptide chains interacting
• Insulin and haemoglobin

Question 12

Digestion definition

Answer 12

Macromolecules in food are broken down into their component small-molecule subunits

Question 13

How are proteins digested in the stomach?

Answer 13

Low pH

Question 14

What is pepsin?

Answer 14

Proteolytic enzyme which cleaves proteins into smaller peptides at pH 2

Question 15

After the stomach, where is protein digested?

Answer 15

Small intestine where it is exposed to proteolytic enzymes

Question 16

How does the pancreas help to digest protein?

Answer 16

Produces proteolytic enzymes which produces a mixture of amino acids and oligopeptides

Question 17

How is the protein further broken down?

Answer 17

By membrane bound enzymes where it is absorbed as amino acids, di and tripeptides

Question 18

Where do amino acids go in the body?

Answer 18

Epithelial cells then into capillaries and plasma where it can be oxidised to provide energy

Question 19

Why are amino acids required?

Answer 19

Protein synthesis

Question 20

Name the 4 functions of protein synthesis

Answer 20

Structure, protection, enzymatic, transport/communication

Question 21

What is deamination?

Answer 21

Removal of the amino group

Question 22

What are the products of deamination?

Answer 22

Ammonia and oxoacid

Question 23

What is another process for amino acids?

Answer 23

Transamination

Question 24

What is transamination?

Answer 24

When an amino acids becomes a different amino acid via de-novo synthesis

Question 25

How is protein needed estimated?

Answer 25

The amount of nitrogen needed to reach nitrogen equilibrium in adults

Question 26

What is the nitrogen requirement for children?

Answer 26

Positive balance

Question 27

How do you calculate protein requirements?

Answer 27

Nitrogen balance x 6.25